Vicor VI-J00 Family DC-DC Converters and Configurable Power Supplies - Manual (Page 45)

Design Guide & Applications Manual
For VI-200 and VI-J00 Family DC-DC Converters and Configurable Power Supplies
VI-200 and VI-J00 Family Design Guide Rev 3.5 vicorpower.com
Page 44 of 98
Apps. Eng. 800 927.9474 800 735.6200
gate of the FET to a voltage in excess of its source. In the
case where multiple DC-DC Driver modules are connected
to one IAM, an external charge pump through the PARALLEL
pin (connected to the gate of the FET) must be added to
ensure that the FET remains enhanced in the event GATE
OUT enhancement is lost (Figure 14 – 4). The additional
circuitry, C2, D1 and D2 are added externally to charge
pump through the PARALLEL pin.
Shut down of the DC-DC converters is accomplished by
saturating Q2 during an input overvoltage to prevent
possible damage to the converters. The IAM will automatically
restart when the input overvoltage is reduced to within
the input voltage range.
If the long term transient withstand specifications are
exceeded, the recommended external fuse will clear.
INPUT CURRENT
Inrush current is a function of the number of DC-DC
converters that are connected to the input attenuator
module (modules are not gated off at turn-on) and the
amount of external capacitance added between the Input
Attenuator Module and the DC-DC converter. The inrush
current specification is 125% of steady state input current
for 10 ms. To avoid excessive dissipation in the element
controlling the inrush (Q1), the following maximum values
of external capacitance must be adhered to.
14. Input Attenuator Module (IAM / MI-IAM)
0.1 1 10ms 100 1000
100V
Normal Operating Area
I.S.W.
Full Load
100V
Standard Wide Range
24 V Inputs
0.1 1 10ms 100 1000
800V
Normal Operating Area
I.S.W.
Full Load
300 V Input
S.D.
160V
0.1 1 10ms 100 1000
Normal Operating Area
I.S.W.
Full Load
48 V Input
R.E.
276V
Normal Operating Area
I.S.W.
Full Load
0.1 1 10ms 100 1000
48 V Wide Range Input
R.E.
S.D.
R.E. R.E.
32V
21V
36V
18V
S.D.
76V
125V
60V
100V
42V
500V
400V
200V 36V
S.D.
S.D. 100V
500ms 500ms
I.S.W.: Input surge withstand (no disruption of performance)
R.E.: Ratings exceeded
S.D.: Shut down
VO
LT
S-
PE
AK
V
AL
UE
O
F
SP
IK
E
VO
LT
AG
E
TIME (SECONDS)
1s
0 10
100ms
-1 10
10ms
-2 10
1ms
-3 10 -4 10 -5 10 -6 10
-600
-500
-400
-300
-200
-100
0
100
200
300
400
500
600
Ratings Exceeded
Reverse Polarity
50V OVP
VO
LT
S-
PE
AK
V
AL
UE
O
F
SP
IK
E
VO
LT
AG
E
TIME (SECONDS)
1s
0 10
100ms
-1 10
10ms
-2 10
1ms
-3 10 -4 10 -5 10 -6 10
600
400
200
0
200
400
600
800
Ratings Exceeded
Reverse Polarity
500
OVP 400
28 Vdc Input
270 Vdc Input
Safe Operating Area
(1% duty cycle max., Zs = 0.5
Ω, for short duration transient capability refer to specifications)
Figure 14–2 — Safe operating area based on input voltage of IAM
24 V 20 A / 32 V (AGC-20)
24 V “W” 20 A / 36 V (AGC-20)
48 V 20 A / 60 V (3AB-20)
48 V “N” 20 A / 80 V (3AB-20)
300 V 5 A / 250 V Bussman PC-Tron
28 V 20 A / 250 V (3AB-20 or F03A, 125 V, 20 A)
270 V 5 A / 250 V Bussman PC-Tron or F03A, 250 V, 4 A
Table 14 –3 — Recommended fusing based on input voltage
Input Voltage Recommended Fuse
24 Vdc (21 – 32 V) 470 µF
24 Vdc (18 – 36 V) 470 µF
28 Vdc (18 – 50 V) 390 µF
48 Vdc (42 – 60 V) 220 µF
48 Vdc (36 – 76 V) 120 µF
270 Vdc (125 – 400 V) 27 µF
300 Vdc (200 – 400 V) 27 µF
[a] Capacitance should be distributed across the input of each
DC-DC converter. (C1, Figure 14–3)
Table 14 –4 — Recommended distributed capacitance on input of
DC-DC converter(s)
Input Voltage Maximum Capacitance [a]